It isn't that Salmon one day really needed $200 from Citibank.
What happened was that on March 11th, 2013, he made a flurry of
transactions (paying off credit cards etc.), and briefly overdrew
his account by $112.56.

Instead of taking that money from his savings account, Citi
rounded up to the nearest hundred and force fed Salmon a loan.

The bank never told him about this loan, instead burying it in
his statement. Then, when Salmon tried to pay off the loan in
full, Citi insisted that he could only make minimum payments at
an interest rate of 13.25%.

This is a yuppie overdraft: rather than charge
me $35 a pop for overdrawing my account, Citibank just rounds any
negative balance up to the nearest $100, and transfers that sum
over from something wonderfully called a “Checking Plus” account.
Which is what they call an overdraft line of credit. Naturally,
when my paycheck arrived four days later, it went into my
checking account, which is separate from my Checking Plus account
. As a result, ever since then, I’ve had a steadily positive
balance in my checking account which has been larger than the
amount I owe on its overdraft facility. And ever since then, Citi
has been quietly paying off the loan at a rate of $12 or so a
month, in the hope that I would never notice it. After all, any
sentient being, upon seeing this situation, would of course pay
the entire loan off immediately.

This, Salmon points out, is how banks are able to offer us all
"free checking." Nice right?

Business Insider reached out to Citigroup for comment, but have
yet to hear anything. We'll keep you posted.